From a retired professional (non-electrician) instructor: The simplicity, clarity and delivery of your tutorials is the best I've ever seen. So many things demystified. Many thanks, John
Having been in the industry for the past 30 years, what a very good way for a refresher. Tutorials are excellent and they are my first port of call. Thank you John, and i do hope you carry on passing your knowledge on forever.
I Hope everyone saw that great tip you offered for Testing an RCD without tripping any upstream devices, that is something I was never aware of in my 40yrs in the Industry, thank you for that little gem. By the way, that Test Button was [I am talking decades ago] used to stop the RCD becoming Dormant and Locked, hence "Test Weekly" used to be the lable that came with the good brands. Mr Spence Eng
Thank You, John! I had this "caravan park" type of situation yesterday. I had to test an RCD and there was other RCD behind it and of course the one that i wasn't testing tripped first and i didn't know how to workaround it.. but now i know, thanks to this video.
what a great well produced video audio was clear and crisp many people just talk nonsense and confuse the situation but you just talked facts and didn't waffle on this video is a credit to the TH-cam community
We test touring caravans on site or at customers home, for this situation it is very simple to use an isolating transformer inline to avoid tripping anything up stream
The Tests to perform are to be conducted on the RCD device "Before mounting into the CU" or " after mounted and energized in CU" ? The 1st test is really testing the Device compared to the 2nd tests which is Test in the System. Grateful for clarification. TQVM
What’s better when testing the RCD, leave all the loads on or remove the loads and just have the RCD? Just wondered if whether I’ll get more accurate results by testing the RCD before having any circuits connected.
How do you do a ramp test If you have an RCD main switch on an old fuse board, would you still do it through a socket on a ring or can it be done at the rcd ??? Thanks
RCD = GFCI, trips when there is an imbalance between L&N caused by an earth fault. MCB = circuit breaker, trips on overload or short circuit. AFCIs are AFDDs here, arc fault detection device.
is it important to connect load side at terminals 2 and N and grid side at terminal 1 and N, or can i connect load side at terminal 1 and N and RCD will work perfectly fine?
Hi jw with the new regs and type a rcds. If installing a socket on a existing circuit for a 13 amp single oven would this need to be type A or dose 531.3.3 mean this is fixed equipment and is okay on ac type still.
Type A is required, as a socket outlet could be used to connect other devices, and most ovens have electronic timers now which can have DC components so are not suitable for Type AC even if they are wired in permanently.
@@jwflame okay jw so even a fused spur would not work on ac type rcd any more needs to be type A. So it would have to something like a cheap gas cooker that just has a spark and nothing else would be okay on type ac. Thats going to please a lot of customers when I start telling them lol
Good video tutorial. I would've done a test with ground/green probe connected to the outlet neutral of the rcd , to show/simulate that the one rcd connected in series would not trip. You already explained it, but could be good just for visual purpose 😉. Good job anyway!
Great video. Two questions: 1. Could you possibly do a video on how to use multifunction testers, whether they be Fluke-Robin, Kewtech or Megger, as you explain all the functions so clearly; 2. I've installed three distribution boards in a building, they are all supplied from an MEM switchgear panel containing three 63 amp fuses each of which is the link between the incoming supply and the cable to each board. Two of the cables are fine, supplying power without a problem, but the third cable will not power up when connected. Power is coming in, but not being transmitted through the fuse to the cable. I have pulled out the fuse link housing between the supply and load sides, and it houses a 63 amp Bussman fuse. Could this be a problem with the fuse, the housing or the board, and how can I test the fuse? At the moment, I only have a Kewtech voltage tester, I don't yet have a mutimeter or multifunction tester. Thank you.
David Sakho 1 - Yes, other testing videos are planned. 2 - A failed fuse is most likely from the description given, any multimeter or continuity tester can be used to test the fuse. However before replacing it, the cause of the failed fuse should be identified.
John I am just starting out and would like a fluke installation tester but was wondering what would be good to start off with for function and price? Would appreciate your advice thanks
Thanks Mr JW for ur valuable videos.... Iam wondering how to test a 3ph RCD 300mA using MTF1731 at the DB, where I tried several times won't tripped at I1 & I5 (times) injunction
When you've got a simple circuit with no equipotential bonding etc, you expect a ballpark figure of Zs=Ze+(R1+R2). While British General RCDs seem to test OK regarding trip times and currents as you have shown, I find that for some reason they add about 0.5 Ohms to the Zs test result of connected circuits. In a lot of cases that can make the difference between a pass and fail. Other makes of RCD do not seem to affect the Zs test result in this way. Have you noticed anything similar?
Hi John, I have finished installing shore power to my little boat. I spent the afternoon trying to get the RCD to switch on. I have not managed to get the switch lever to remain up. Not while totally disconnected from any wires nor while wired up and connected to the pontoon power supply. Using a little Fluke device I established that the wiring from the shore power was correct and on. A friend suggested that the RCD was broken saying that even when not connected, for example straight out the box packaging, the black switch lever should remain in the up position if clicked on. I would like to know if you agree. If that is the case then it is for the bin. Many thanks, Mike
+Traveller32sloop If it's the style shown in the video then it should latch on even with no power. Faulty if not. There are active RCDs which only latch in the presence of power and disconnect when power is removed, but they are normally only used in individual socket outlets or similar, not for consumer units.
Hi John Love the clips, I'm looking for advice I have a Fluke 1651 MFT from 2007 its never been used and as new, do you think in modern day eicr situations that this tester would be suitable for use and can it perform all tasks required to 18th edition, I'm a mature student 1st year looking for some sound advice - thank you in advance.
Yes, all of the tests it can do are still valid - very little has changed for testing since then. That one was the basic model so doesn't have earth electrode testing or phase sequence.
Hi John, Yes you are right it was the base model at the time of purchase, I did Part P Full scope test with EAL and decided I would carry on with my electrical training but career dictated otherwise, I am now on the long haul C+G 2365 route - but my training is well underway, Thank you for your advice and keep the Clips Coming :)
John, earlier today Wednesday 17th April, I intended cutting my grass using my electric mower. However, after plugging in my Masterplug RCD, and testing it as expected, the test light came on initially, went off as expected so I assumed that it was all systems go. Unfortunately, I could not start the mower so could the RCD be past its use by date? Mower works fine when plugged in the mains directly.
Two possibilities - either the RCD plug is defective, or the lawnmower has a fault which is preventing the RCD from switching on. Try some other item like a kettle with the RCD.
should 30mA RCD's be in series i.e one RCD circuit powering a sub-main (GARAGE UNIT) where the main switch on the sub-main is RCD main switch 30mA or do you go off the high integrity side or install a time delay RCD?? which is best practice?
It's poor design to have two or more RCDs of the same type, as when a fault occurs there is no way to know which will trip first. Sometimes both will trip. This is not dangerous, but would be inconvenient if the house was disconnected due to a fault in the garage. A time delay RCD will resolve the problem, but the real answer is to only have the RCD for the final circuits, submains do not normally require RCDs.
No, an RCD does not trip when overloaded. The trip will either be caused by one or both items having some leakage to earth (heating elements often do), or there is a fault between neutral and earth somewhere in the installation and the combined load of both appliances is sufficient to cause enough current to flow via the N-E fault and trip the RCD.
Thanks for making this video! I hope that you please want to advice me. I have a RCD type A going out to a 2 phase outlet (no ground) I am wondering if it is safer to use a isolation transformer for DUT or just the main? As you show the RCD does trigger at 30mA but would never trigger if an isolation transformer is between the DUT and the RCD. But all on TH-cam (Americans) do say isolation transformer is the only safe way.
I saw an electrician testing RCD's at the board recently where previously I had only seen rcd's tested using a PAT tester, requiring it to be plugged into an outlet socket designated to a particular rcd. this seemed to save lots of time but I was curious if this form of testing passes Australian standards and is as accurate with the trip times? I take it this is basically what you've don't in this video
David Jensen There should be no difference between testing at the board or at a socket - the circuit wires are still connected in either case. Not familiar with the Australian standards but it's totally acceptable to do it either way in the UK. Testing at the board is often the only way, particularly for circuits which do not have socket outlets.
Hi John...when testing RCBOs am I correct in assuming that they should be tested in the same way but one at a time? Can they all be connected to line, neutral & earth while testing or should only the RCBO being tested be connected. Thanks in advance.
I've just realised that it would have to be each one separately otherwise you couldn't verify that each one is functioning correctly. You may have guessed that I'm still in training.
Perhaps a silly question, but could one theoretically test that an RCD trips using just a battery, or a signal generator outputting a similarly low voltage?
Hi John, Are you using the RCD through an isolation transformer like on your other videos to prevent the test tripping your house RCD? If so what make is this transformer and where did you get it? Thanks.
+Daniel Brown Yes, isolating transformer was used. The one I have is rather old and has no make on it. They can be purchased new but are rather expensive. Used ones can usually be found cheaply on ebay by searching for 'safety isolation transformer' '230 isolation transformer' and similar.
Hi John, I am considering building a small unit to test RCDs ( purely a project, not to be a professional meter ) . Do you have any ideas what electronics these meters use to create the leakage current? I was considering switching some power resistors with relays, to create the various currents required, but is seems a rather bulky solution, especially to get also the x0.5 and x5. Also, the tripping current resolution will be crap. Suggestions?
Hello....a little confusing and unless I have interpreted wrongly...but you seem to be suggesting, that 63A and 630A are both the max before the switch 'gives-up'...apologies...which is it? best regards
In (63A) is the maximum current while the RCD is in use. Im (630A) is the maximum current when the RCD is closed, i.e. a switch on surge. Inc (6000A) is the maximum current when a fault occurs such as a short between L&N or L&E. If any of those are exceeded, the device will probably be damaged. Current values are for the particular RCD in the video, they will be different for other RCDs but the definitions are the same.
RMS, and an 8K resistor will give 30mA at 240V. If you do use a resistor to test, bear in mind that if the RCD doesn't open, the resistor will be a 7W heater and get very hot / be destroyed depending on it's power rating.
Hi John I'm a fully qualified NICEIC approved contractor and recently installed a MK split load board amendment 3 to replace a old consumer unit on a TNCS system. Carried out all dead tests including IR testing and all out going ccts were completely clear. How ever when energised and carry out a RCD test it fails on times one and test button will not operate. When out going neutral is disconnected it passes its x1&x5 0-180 degrees and trip button functions. I narrowed the problem down to a compression fault in a radial boiler supply however the cores are completely clear between each other and disconnected from the boiler. I'm completely baffled what could cause this I've spoken to Mk and were to baffled along with the NICEIC. Any ideas?
@@andyevanscreations so are you saying the RCD tested ok without connecting the circuit, then when you connect the circuit it doesn't trip at all or ...? Oh the test button don't work but the 5x trip work but not the 1x?
Hi John thanks for these good videos ... I have always thought that 63A is the braking or tripping current rather than working current on the particular rcbo. And unfortunately tripping current 6kA . what would be the best rcbo to use to protect the wires from over heating ? thanks
It's an RCD only not an RCBO. 63A is the maximum continuous current. I believe 6000A is the absolute maximum fault current to reliably break the arc and not catch fire or explode. Consider a low impedance high current source can sustain very high fault current into a dead short!
Hi John, this was a really helpful video. I have a question about rcd blinding. Would a test like this show up a blinding issue? Or how could I test for it? Would I have to directly measure for any pulsating dc currents? I studied to become a domestic installer about 6 years ago now, but only left my previous job recently, so i'm re-studying. I have to do my 18th regs and came across the effects of blinding there, though I can't seem to find much else on it elsewhere. Could you please help clarify
The only real test is whether the RCD trips - testing of RCDs should be done with the installation loaded as in normal use, with equipment switched on, and the testing done at a time of day where the installation is actually being used normally.
Ok thanks John, not a simple push of the test button then! Might be worth doing an extra test at a later time if these conditions aren't met at initial testing?
Do we do rcd test just on sockets and applied for all the circuits or should we have seperate rd test for each circuits like lighting? If so wouldn't be dangerous to be exposed to live circuits? Thanks H
If there are several RCDs, they all need to be tested. One RCD with several circuits connected only needs to be tested once, it's the RCD being tested not the circuit wiring.
Hi John ! I love your videos very much. I need your help , I wish to buy the fluke 1652c or the megger mft1730 what do you think the better for me to buy ? best regards !
Hi John, love your videos, keep it up. Can I ask, what is that connector pedal thingy behind your Fluke mft seen 2.20 into the video. I use to have one and want to buy another, but have no idea what they're called. Thanks in advance.
Hi John Love your vids always clear and informative...I just thought something to add/ do a vid of would be if there is a N-E fault on another circuit to one being worked on that this can stop the test button working due to parallel earth paths, and the process of tracing them out to identify affected circuit. Ie main earth cont, bonds out, then if not to those removing neutrals to identify circuit (also a good place to drop in a mention of the trusty wander lead). Hope this is received well and not taken as a critasism as it's not. Looking forward to watching more of your vids. Nat
Hi John thanks for the upload, could you do a video on a rcd test with a three phase three wire with no neutral connection on the load side of the RCCB? Was wondering if it would still trip. Many thanks.
Hi John. Thanks for these great videos. Could you do a video explaining the use of the white fly lead from an RCBO to earth bar Some RCBo's have them and some do not. Thank you in-advance.
Lorenzo Taurino The test button gives an indication it is working, however they should be tested when installed to ensure they trip within the required time.
Hi John, you guys are home to 'Megger' yet the last two English electrical videos I've looked up, you (and the English electrician in the other video) have both been using Fluke! Is there any particular reason for that, like is Megger too expensive, is Fluke a better make? It's that I've just bought myself a Megger MFT 1835 (not being an electrician and all, and not knowing much about testers, but really keen to learn) and seeing you 'English' technicians using Fluke is kinda unnerving! Thanks. Great vids by the way.
From a retired professional (non-electrician) instructor: The simplicity, clarity and delivery of your tutorials is the best I've ever seen. So many things demystified. Many thanks, John
Having been in the industry for the past 30 years, what a very good way for a refresher. Tutorials are excellent and they are my first port of call.
Thank you John, and i do hope you carry on passing your knowledge on forever.
I Hope everyone saw that great tip you offered for Testing an RCD without tripping any upstream devices, that is something I was never aware of in my 40yrs in the Industry, thank you for that little gem.
By the way, that Test Button was [I am talking decades ago] used to stop the RCD becoming Dormant and Locked, hence "Test Weekly" used to be the lable that came with the good brands.
Mr Spence Eng
Thank You, John! I had this "caravan park" type of situation yesterday. I had to test an RCD and there was other RCD behind it and of course the one that i wasn't testing tripped first and i didn't know how to workaround it.. but now i know, thanks to this video.
what a great well produced video audio was clear and crisp many people just talk nonsense and confuse the situation but you just talked facts and didn't waffle on this video is a credit to the TH-cam community
You are like the Richard Attenborough of electrical theory. ❤ Great and relaxing presentation 😊
superb video John, you are reaching out to a big Audience on here.. keep the good work up. all the best.
Man ..JW . Thanks for uploading such stuff . we all appreciate your work. Thanks again.
Nice clear stuff, got my first EIC cert to complete soon, all your videos are helping me to remember what I learnt last year. Many thanks.
Your videos are like gold dust. You have helped me tremendously!
John, great advice on how to test an RCD with another RCD on the supply side!
We test touring caravans on site or at customers home, for this situation it is very simple to use an isolating transformer inline to avoid tripping anything up stream
Thanks John. I really liked the tip about how to test when there are two RCD's in series. Could prove useful.
Fantastic delivery and tutorial I’ve learned so much from you, please keep up doing videos John
Wow John your killing it with the subs now mate! Good on ya! Your a god among mortals?! 👍
Very logical & clear (as all the videos you've made are) - excellent job.
The Tests to perform are to be conducted on the RCD device "Before mounting into the CU" or " after mounted and energized in CU" ? The 1st test is really testing the Device compared to the 2nd tests which is Test in the System. Grateful for clarification. TQVM
Tests are done when it's installed in the consumer unit, and after most of the other tests of the circuit wiring have been done.
you have your 230vac blue and brown cables wired in at the top of the rcd are they live
I still get the same result with just the active and earth attached. Does the neutral need to be attached for testing the trip time?
What’s better when testing the RCD, leave all the loads on or remove the loads and just have the RCD?
Just wondered if whether I’ll get more accurate results by testing the RCD before having any circuits connected.
How important is the earth fault loop impedance for the breakers to trip < 0.4 secs if you have everything on an RCD
Hi John - got one at the moment where Im only getting a result on one half of the sine wave - 0degrees. Any suggestions please?
How do you do a ramp test If you have an RCD main switch on an old fuse board, would you still do it through a socket on a ring or can it be done at the rcd ??? Thanks
I love this KIS method "Keep It Simple" for the stupid like me!!! keep it up, John.
That was extremely clear on how to test RCDs John. 👍
can load and line side be confused, will RCD work perfectly fine? can you make what test results will be if load and line sides are opposite.
What is the difference between an rcd, and a MCB? Here in the states we have GFCI devices and AFCI devices.
RCD = GFCI, trips when there is an imbalance between L&N caused by an earth fault.
MCB = circuit breaker, trips on overload or short circuit.
AFCIs are AFDDs here, arc fault detection device.
im in the us. i keep hearing about these rcd's, im guessing this is the same as a gfci breaker (as opposed to a gfci outlet) here in the us?
Learned a lot from your video on how to test RCD's. Thanks.
Really enjoy you videos, would love to see you do 2 or 3 a week.
is it important to connect load side at terminals 2 and N and grid side at terminal 1 and N, or can i connect load side at terminal 1 and N and RCD will work perfectly fine?
Depends on the RCD - it's OK with some, but not others. Check specifications from the manufacturer.
Thankyou for this, Can you test the RCD without disconnecting the load?
That's a really good video. Thanks for taking the time to do it.
Excellent work . Provide a lot of use full information
How would the same test be performed on a bipolar RCD fed 2 phases in instead of phase and neutral?
So if the difference in current coming back is 30 mA or more, it will switch off??
Hi jw with the new regs and type a rcds. If installing a socket on a existing circuit for a 13 amp single oven would this need to be type A or dose 531.3.3 mean this is fixed equipment and is okay on ac type still.
Type A is required, as a socket outlet could be used to connect other devices, and most ovens have electronic timers now which can have DC components so are not suitable for Type AC even if they are wired in permanently.
@@jwflame okay jw so even a fused spur would not work on ac type rcd any more needs to be type A. So it would have to something like a cheap gas cooker that just has a spark and nothing else would be okay on type ac. Thats going to please a lot of customers when I start telling them lol
well described and explained...like to see some more on testing pfc ect. doing 17th ed in april....cheers
darron higgins Other testing videos are planned.
Good video tutorial. I would've done a test with ground/green probe connected to the outlet neutral of the rcd , to show/simulate that the one rcd connected in series would not trip.
You already explained it, but could be good just for visual purpose 😉. Good job anyway!
Where shall we write the results in the document
Thanks
thanks for taking the time to explaining that.
Great video.
Two questions:
1. Could you possibly do a video on how to use multifunction testers, whether they be Fluke-Robin, Kewtech or Megger, as you explain all the functions so clearly;
2. I've installed three distribution boards in a building, they are all supplied from an MEM switchgear panel containing three 63 amp fuses each of which is the link between the incoming supply and the cable to each board. Two of the cables are fine, supplying power without a problem, but the third cable will not power up when connected. Power is coming in, but not being transmitted through the fuse to the cable. I have pulled out the fuse link housing between the supply and load sides, and it houses a 63 amp Bussman fuse. Could this be a problem with the fuse, the housing or the board, and how can I test the fuse? At the moment, I only have a Kewtech voltage tester, I don't yet have a mutimeter or multifunction tester.
Thank you.
David Sakho 1 - Yes, other testing videos are planned.
2 - A failed fuse is most likely from the description given, any multimeter or continuity tester can be used to test the fuse. However before replacing it, the cause of the failed fuse should be identified.
***** Thank you.
Your videos are very helpful and distinguished, thank you very much
John I am just starting out and would like a fluke installation tester but was wondering what would be good to start off with for function and price? Would appreciate your advice thanks
Thanks Mr JW for ur valuable videos.... Iam wondering how to test a 3ph RCD 300mA using MTF1731 at the DB, where I tried several times won't tripped at I1 & I5 (times) injunction
When you've got a simple circuit with no equipotential bonding etc, you expect a ballpark figure of Zs=Ze+(R1+R2).
While British General RCDs seem to test OK regarding trip times and currents as you have shown, I find that for some reason they add about 0.5 Ohms to the Zs test result of connected circuits.
In a lot of cases that can make the difference between a pass and fail.
Other makes of RCD do not seem to affect the Zs test result in this way.
Have you noticed anything similar?
Please make a video of loop impedance testing with the fluke
Good review btw :)
Great videos. Thanks for the trip to avoid tripping RCD upstream. Fantastic!
If earth and neutral is shorted after the RCD. Will the RCD then trip when the short happens, or not at all, even if there is a fault?
Depends on a number of factors - what load is connected and the impedance of the PE and N conductors.
I did rcd test on final circuit and when i did test x5 it showed 0.0 also on 180 degrees it was 0.0 is it normal . 30 mA rcd tested.
Hi John,
I have finished installing shore power to my little boat. I spent the afternoon trying to get the RCD to switch on. I have not managed to get the switch lever to remain up. Not while totally disconnected from any wires nor while wired up and connected to the pontoon power supply. Using a little Fluke device I established that the wiring from the shore power was correct and on.
A friend suggested that the RCD was broken saying that even when not connected, for example straight out the box packaging, the black switch lever should remain in the up position if clicked on.
I would like to know if you agree. If that is the case then it is for the bin.
Many thanks, Mike
+Traveller32sloop If it's the style shown in the video then it should latch on even with no power. Faulty if not.
There are active RCDs which only latch in the presence of power and disconnect when power is removed, but they are normally only used in individual socket outlets or similar, not for consumer units.
John,
Will you be doing any updates to this playlist, for the likes of Type A RCDs ,filling out 18th edition test certificates, solar P.V and EV?
Hi John Love the clips, I'm looking for advice I have a Fluke 1651 MFT from 2007 its never been used and as new, do you think in modern day eicr situations that this tester would be suitable for use and can it perform all tasks required to 18th edition, I'm a mature student 1st year looking for some sound advice - thank you in advance.
Yes, all of the tests it can do are still valid - very little has changed for testing since then. That one was the basic model so doesn't have earth electrode testing or phase sequence.
Hi John, Yes you are right it was the base model at the time of purchase, I did Part P Full scope test with EAL and decided I would carry on with my electrical training but career dictated otherwise, I am now on the long haul C+G 2365 route - but my training is well underway, Thank you for your advice and keep the Clips Coming :)
Great video John
very clearly explained
Clearly explaination. Superb !!
I usually do between L pipe in load side of red and Earth busbar . Is it correct ?
That will work - it just needs to create an imbalance between each side of the RCD.
John, earlier today Wednesday 17th April, I intended cutting my grass using my electric mower. However, after plugging in my Masterplug RCD, and testing it as expected, the test light came on initially, went off as expected so I assumed that it was all systems go. Unfortunately, I could not start the mower so could the RCD be past its use by date? Mower works fine when plugged in the mains directly.
Two possibilities - either the RCD plug is defective, or the lawnmower has a fault which is preventing the RCD from switching on.
Try some other item like a kettle with the RCD.
@@jwflame Many thanks for your suggestion, I didn't think of doing that!
That In (Rated Current) is that the same in all countries, or at least in Europe??
should 30mA RCD's be in series i.e one RCD circuit powering a sub-main (GARAGE UNIT) where the main switch on the sub-main is RCD main switch 30mA or do you go off the high integrity side or install a time delay RCD??
which is best practice?
It's poor design to have two or more RCDs of the same type, as when a fault occurs there is no way to know which will trip first. Sometimes both will trip. This is not dangerous, but would be inconvenient if the house was disconnected due to a fault in the garage.
A time delay RCD will resolve the problem, but the real answer is to only have the RCD for the final circuits, submains do not normally require RCDs.
@@jwflame Thank you
Great video JW!
Is correct that the rcd trips instead of the main in an overload? Connected load is an oven and a toaster fed from different branch circuits.
No, an RCD does not trip when overloaded.
The trip will either be caused by one or both items having some leakage to earth (heating elements often do), or there is a fault between neutral and earth somewhere in the installation and the combined load of both appliances is sufficient to cause enough current to flow via the N-E fault and trip the RCD.
+John Ward Thanks John. How often shall we test RCD? Mostly it is written on the device " push monthly "or "test monthly".
Monthly will do, some suggest quarterly. It's mainly to prevent the mechanical parts inside sticking.
Is it acceptable that an 30mA ELCB tripped with the result of 110ms at the 30mA test.
Yes, the maximum is either 200ms or 300ms depending on what standard it was designed to.
@@jwflame Thanks for your answer, we followed IEC61008. I doubted what we have as I saw the RCD you tested tripped within 40ms at 30mA.
Thank you very much very GOOD explanation step by step I enjoyed
Thanks for making this video!
I hope that you please want to advice me. I have a RCD type A going out to a 2 phase outlet (no ground)
I am wondering if it is safer to use a isolation transformer for DUT or just the main?
As you show the RCD does trigger at 30mA but would never trigger if an isolation transformer is between the DUT and the RCD.
But all on TH-cam (Americans) do say isolation transformer is the only safe way.
I saw an electrician testing RCD's at the board recently where previously I had only seen rcd's tested using a PAT tester, requiring it to be plugged into an outlet socket designated to a particular rcd. this seemed to save lots of time but I was curious if this form of testing passes Australian standards and is as accurate with the trip times? I take it this is basically what you've don't in this video
David Jensen There should be no difference between testing at the board or at a socket - the circuit wires are still connected in either case.
Not familiar with the Australian standards but it's totally acceptable to do it either way in the UK. Testing at the board is often the only way, particularly for circuits which do not have socket outlets.
thanks John.....I appreciate the feedback.
Hi John...when testing RCBOs am I correct in assuming that they should be tested in the same way but one at a time? Can they all be connected to line, neutral & earth while testing or should only the RCBO being tested be connected. Thanks in advance.
I've just realised that it would have to be each one separately otherwise you couldn't verify that each one is functioning correctly. You may have guessed that I'm still in training.
Perhaps a silly question, but could one theoretically test that an RCD trips using just a battery, or a signal generator outputting a similarly low voltage?
Do you carry out the test on the furthest point from the circuit the rcd is on ?
You could do, but it isn't necessary. Can be done at any convenient point of the circuit.
Hi John, Are you using the RCD through an isolation transformer like on your other videos to prevent the test tripping your house RCD? If so what make is this transformer and where did you get it? Thanks.
+Daniel Brown Yes, isolating transformer was used. The one I have is rather old and has no make on it. They can be purchased new but are rather expensive.
Used ones can usually be found cheaply on ebay by searching for 'safety isolation transformer' '230 isolation transformer' and similar.
Thats a EN61008 which means no overload protection, so these will trip on short circuit then I assume?
No, they have no overcurrent or short circuit protection. It's just an RCD.
@@jwflame ah now I understand, thanks John
today when testing a RCd the trip current equal to 0 and tripping time equal to 0 . is it damaged RCD
Very informative as usual.
Great video, very helpful. Thank you
Hi John, I am considering building a small unit to test RCDs ( purely a project, not to be a professional meter ) . Do you have any ideas what electronics these meters use to create the leakage current? I was considering switching some power resistors with relays, to create the various currents required, but is seems a rather bulky solution, especially to get also the x0.5 and x5. Also, the tripping current resolution will be crap. Suggestions?
Have you ever used Chint rcbo (s) ? Are they good
Hello....a little confusing and unless I have interpreted wrongly...but you seem to be suggesting, that 63A and 630A are both the max before the switch 'gives-up'...apologies...which is it? best regards
In (63A) is the maximum current while the RCD is in use.
Im (630A) is the maximum current when the RCD is closed, i.e. a switch on surge.
Inc (6000A) is the maximum current when a fault occurs such as a short between L&N or L&E.
If any of those are exceeded, the device will probably be damaged.
Current values are for the particular RCD in the video, they will be different for other RCDs but the definitions are the same.
What is used for the trip calculation peak, rms, or pp. VAC. ??.
RMS, and an 8K resistor will give 30mA at 240V. If you do use a resistor to test, bear in mind that if the RCD doesn't open, the resistor will be a 7W heater and get very hot / be destroyed depending on it's power rating.
How many years have you been a spark for?
Hi John. How about testing a 3 poles MCCB?..
Hi John, does it matter if the supply comes in at the bottom and the load at the top (opposite way round to what you have it)?
+si myob Not usually, although check the specifications from the manufacturer before using it like that.
Thanks
some rcd
Hi John I'm a fully qualified NICEIC approved contractor and recently installed a MK split load board amendment 3 to replace a old consumer unit on a TNCS system. Carried out all dead tests including IR testing and all out going ccts were completely clear. How ever when energised and carry out a RCD test it fails on times one and test button will not operate. When out going neutral is disconnected it passes its x1&x5 0-180 degrees and trip button functions. I narrowed the problem down to a compression fault in a radial boiler supply however the cores are completely clear between each other and disconnected from the boiler. I'm completely baffled what could cause this I've spoken to Mk and were to baffled along with the NICEIC. Any ideas?
Hi Andy did you happen to find out what was causing the fault
Assuming incoming conductors are correctly connected, carry out the RCD with nothing connected on the load side of the terminals.
marky marks I’ve literally only just seen this message. Sorry buddy. No I never got to the bottom of it.
Steve Tang hi yes I tried that and it was clear.
@@andyevanscreations so are you saying the RCD tested ok without connecting the circuit, then when you connect the circuit it doesn't trip at all or ...? Oh the test button don't work but the 5x trip work but not the 1x?
John what results would you record quickest or slow trip times at 0 and 180 degree
Slowest / longest time.
Hi John thanks for these good videos ... I have always thought that 63A is the braking or tripping current rather than working current on the particular rcbo. And unfortunately tripping current 6kA . what would be the best rcbo to use to protect the wires from over heating ? thanks
It's an RCD only not an RCBO.
63A is the maximum continuous current. I believe 6000A is the absolute maximum fault current to reliably break the arc and not catch fire or explode. Consider a low impedance high current source can sustain very high fault current into a dead short!
Hi John, this was a really helpful video. I have a question about rcd blinding. Would a test like this show up a blinding issue? Or how could I test for it? Would I have to directly measure for any pulsating dc currents?
I studied to become a domestic installer about 6 years ago now, but only left my previous job recently, so i'm re-studying. I have to do my 18th regs and came across the effects of blinding there, though I can't seem to find much else on it elsewhere. Could you please help clarify
The only real test is whether the RCD trips - testing of RCDs should be done with the installation loaded as in normal use, with equipment switched on, and the testing done at a time of day where the installation is actually being used normally.
Ok thanks John, not a simple push of the test button then! Might be worth doing an extra test at a later time if these conditions aren't met at initial testing?
Do we do rcd test just on sockets and applied for all the circuits or should we have seperate rd test for each circuits like lighting? If so wouldn't be dangerous to be exposed to live circuits?
Thanks
H
If there are several RCDs, they all need to be tested. One RCD with several circuits connected only needs to be tested once, it's the RCD being tested not the circuit wiring.
John Ward
Thanks John
Great help
Thank you very informative❤
Hi John ! I love your videos very much.
I need your help , I wish to buy the fluke 1652c or the megger mft1730 what do you think the better for me to buy ?
best regards !
Hi John, love your videos, keep it up. Can I ask, what is that connector pedal thingy behind your Fluke mft seen 2.20 into the video. I use to have one and want to buy another, but have no idea what they're called. Thanks in advance.
Cliff Quicktest QT1. Video about it here: th-cam.com/video/ZCeOYv1kuWk/w-d-xo.html
John Ward Thank you!
great info, Id like to get a Fluke 1653-54 and use it to test here in the US -- Please do more videos ...
Sounds like an airline pilot explaining it.
hahahahaha 100%, but it was informative for me
Reassuring!!!
Hi John
Love your vids always clear and informative...I just thought something to add/ do a vid of would be if there is a N-E fault on another circuit to one being worked on that this can stop the test button working due to parallel earth paths, and the process of tracing them out to identify affected circuit. Ie main earth cont, bonds out, then if not to those removing neutrals to identify circuit (also a good place to drop in a mention of the trusty wander lead).
Hope this is received well and not taken as a critasism as it's not.
Looking forward to watching more of your vids.
Nat
Hi John thanks for the upload, could you do a video on a rcd test with a three phase three wire with no neutral connection on the load side of the RCCB? Was wondering if it would still trip. Many thanks.
Mr.John is rcd able to trip without earthing?
thanks for this video.
Hi John. Thanks for these great videos.
Could you do a video explaining the use of the white fly lead from an RCBO to earth bar
Some RCBo's have them and some do not.
Thank you in-advance.
Could you help me, I need an explanation about how connect rcd eaton ( 4 pole). Model DRCM 40-4-003-U
3 phases and neutral on one side, the same 3 phases and neutral on the other side.
@@jwflame if un the output only i connect 3 phases without neutral?
That's ok, if the circuit doesn't have a neutral.
Thanks John great video
Great video👍
Is it okay to rely on the rcd as long as the test button trips it off?
Lorenzo Taurino The test button gives an indication it is working, however they should be tested when installed to ensure they trip within the required time.
Brilliant thanks John
Hi John, you guys are home to 'Megger' yet the last two English electrical videos I've looked up, you (and the English electrician in the other video) have both been using Fluke! Is there any particular reason for that, like is Megger too expensive, is Fluke a better make? It's that I've just bought myself a Megger MFT 1835 (not being an electrician and all, and not knowing much about testers, but really keen to learn) and seeing you 'English' technicians using Fluke is kinda unnerving! Thanks. Great vids by the way.